Eldritch Cows

[Xersaoth]

When a warlock is polymorphed into a cow via wild magic, the cow can still retaliate and blast the wild mage dead.

[chris a gogo]

Because it's not a spell it's an ability, same for spells gained from focuses they are usable for the same reason, only difference is due to the limited uses for the focus spells they will run out of casting where as EB has no limit so just keeps being usable.